Interlocking control apparatus



Dec. 26, 1939. E. M. ALLEN ET AL 2,184,787

INTERLOCKING CONTROL APPARATUS Filed Oct. 26, 1955 8 Sheets-Sheet l IN VEN TORS Earl M Allen and HowcmdA. Thompmorz THEIR ATTORNEY Dec. 26, 1939. E. M. ALLEN ET AL 2,184,787

INTERLOGKING CONTROL APPARATUS V Filed Oct. 26, 1953 8 Sheets-Sheet 2 m fi I 1 T? 4226 V2 10 9 51b 6] 60 59 lj [j V5 61 I 1 62m 64 1 VE T m 66 h n 2 Earl/V. 11916192 5;

E B y llawaPdA. Thompyozz.

j THEIR ATTORNEY Dec. 26, 1939 E. M. ALLEN ET AL 2,184,787

INTERLOCKING CONTROL APPARATUS Filed Oct. 26, 1935 8 Sheets-Sheet 4 b 4 462 Q Q) INVENTOIRS Earl/W. Allen and QR THE/12m! Dec. 26, 1939.

E. M. ALLEN ET AL INTERLOCKING CONTROL APPARATUS Filed Oct. 26, Y 1933 8 Sheets-Sheet 5 ig RMN NNN QNN N EN 1A1 J a WwN wavw Qi ll NMNWN NNNWN J j Dec. 26,. 1939. E. M. ALLEN ET AL INTERLOCKING CONTROL APPARATUS Filed Oct. 26, I933 8 Sheets-Sheet 6 IN VEN TORS Far! MAZZQI and war'a'A. T

THE 11? ATTORNEY Dec. 26, 1939. E. M. ALLEN ET AL INTERLOCKING CONTROL APPARATUS Filed Oct. 26, 1933 8 Sheets-Sheet 7 S R n do E mm M ma m e T HM A 1 2% w H Y B Dec. 26, 1939. E. M. ALLEN ET AL INTERLOCKING CONTROL APPARATUS Filed Oct. 26, 1933 8 Sheets-Sheet 8 m T N Nam m mam T mm} M A m? EH route check network; Fig. 4 shows circuits for controlling signal slotting relays; and Fig. 5

Patented Dec. 26, 1939 UNITED STATES INTERLOCKING CONTROL APPARATUS Earl M. Allen) Swissvale, and Howard A. Thompson, Edgewood, Pa.,assignors to The Union Switch & Signal Company, Swissvale, Pa., a corporation of Pennsylvania Application October 26, 1933, Serial No. 695,294

63 Claims.

Our invention relates to interlocking control apparatus, and is particularly adapted for, though not limited to, the control of railway track switches and signals in a railway switching or interlocking layout.

One feature of our invention is the provision of novel and improved interlocking control apparatus without the use of interlocked levers. Another feature of our invention is the provision of novel and improved indication apparatus associated with such interlocking control apparatus.

The apparatus of our inventionis an improvement over that disclosed in the copending applications Serial No. 323,286, filed December 3, 1928, by Lester E. Spray for Multiple control apparatus; and Serial No. 416,061, filed December 23, 1929, by Howard A. Thompson for Multiple control apparatus.

We will describe three forms of apparatus embodying our invention, and will then point out the novel features thereof in claims.

In the accompanying drawings, Figs. 1 to 5, inclusive, are diagrammatic views showing the component parts of one form of apparatus embodying our invention. More specifically, Figs. 1 and 1 show a typical track, switch, and signal layout, as well as switch control and indication circuits for apparatus embodying our invention; Figs. 2* and 2 show a track model, and switch and signal control levers, together with approach locking circuits and call-on signal control circuits for the layout shown in Figs. 1 andl Fig. 3 shows signal control circuits interconnected to form what we will refer to hereinafter as a parts in each of the views.

Referring first to Figs. 1 and l these drawings show a stretch of double track railway,

tracks ac and bb of'which are interconnectedthrough a crossover ee with which they are respectively joined byswitches H and H and are likewise interconnected by a second crossover 17 with which they are respectively joined by.

Tracks aa and bb are also respectively joined to passing sidings cc switches H and H Similar reference characters refer to similar omitted from the drawings,

and dd by switches H and HR The reference characters I and l designate the rails of track ad, and the reference characters 2 and 2 designate the-rails of track 222).

These rails are divided by insulated joints 3 form a plurality of track sections aA, A-zi, ii 77', 7'7'E, E E B --B, B-mm, mmG, Gl,D and D-d. Each of these track sections is supplied with current by a battery 4 connected across the rails adjacent one end of the section. A track relay,'designated by the reference character T with a distinguishing exponent, is connected across the rails adjacent the opposite end of each track section.

Reference character S, with distinguishing exponents, designates signals which are placed adjacent the points A, B, C, D, E and F, respectively, and which, as here shown, are of the S and S govern westbound traffic moves, that is, moves which are made over the stretch of track from right to left as shown in the drawings.

Each track section in which a switch is located will be referred'to hereinafter as a detector section. Track sections aA and D-d in the rear of signals S and 5*, respectively, and track sections B B and EE' in the rear of signals S and S respectively, will be referred to as approach track sections.

'Each switch I-I is operated by a switch machine or motor designated by the reference character M with an exponent corresponding with that of the reference character H for the switch. Each motor M may be of a fluid pressure type which is provided with a normal control magnet a reverse controlmagnet rr, and a master control or lock magnet'q.

Normal and reverse control magnets 1m and 1T,

for motor M for operating switch H are controlled by a neutral contact ll of a polarized switch control relay m and by a polar contact l2'of the same relay in its normal or its reverse position, respectively. Lock magnet q for motor M is controlled by back contacts of normal and trol circuits for the motor of switch I-I are simi lar to those for motor M and are therefore reverse indication relays designated bythe reference characters 2' and 15 respectively. The con- Normal and reverse control magnets 1m and rr for motors M and M for operating switches H and 1-1, respectively, of crossover 17 are controlled, with the normal magnets nn in series, and with the reverse magnets T7 in series, by a polar contact l2 in its normal or its reverse position, and by a neutral contact H These are contacts of a polarized switch control relay m Lock magnets q for motors M and M are controlled in series by back contacts of normal and reverse indication relays i and t respectively. The control circuits for the motors for operating switches H and H of crossover ee are similar to those for motors M and M and are therefore not shown in the drawings.

Operated in conjunction with switch H is a pole-changer 5. A similar pole-changer is operated in conjunction with switch H Operated in conjunction with switches H and H are pole-changers 5 and 1, respectively. Similar pole-changers are operated in conjunction with switches H and H respectively.

A polarized switch indication relay h is so controlled by pole-changer 5 of switch H that it becomes energized in the normal or the reverse direction according as switch H is operated to its normal or its reverse position, respectively. A second polarized switch indication relay h is similarly controlled in conjunction with switch 1-1 A third polarized switch indication relay h is so controlled by a circuit including pole-changers 6 and l of switches H and H respectively, in series that it becomes energized in the normal or the reverse direction according as switches H and H are operated to their normal or reverse positions, respectively. A fourth polarized switch indication relay h is similarly controlled in conjunction with switches H and H.

A normal indication relay, designated by the reference character 2', and a reverse indication relay, designated by the reference character t, are associated with each switch and are distinguished by exponents corresponding to those of the corresponding switches. Each relay 2' is controlled by a neutral front contact and by a normal polar contact of the polarized indication relay h and of the polarized control relay m for its switch as well as by a back contact of the reverse indication relay t for the same switch. Each relay t is controlled by a neutral front and a re-- verse polar contact of the polarized indicationrelay h and of the polarized control relay m for its switch as well as by a back contact of the normal indication relay 2' for the same switch.

Each switch control relay m is controlled by a lock relay designated by the reference character R with an exponent corresponding to that of the associated switch, and by normal and reverse switch lever repeater relays designated by the reference characters f and g, respectively, with corresponding exponents. A resistor 15 is connected in multiple with the winding of each relay m in order to make the relay m slow in releasing.

Each normal lever repeater relay has a stick circuit controlled by a back contact of the associated reverse lever repeater relay 9, and has a pick-up circuit controlled by a normal contact of a switch lever designated by the reference character 70 with a corresponding exponent, shown in Fig. 2 or 2*, or of a switch lever designated by the reference character y with a corresponding exponent, shown in Fig. 6. Each reverse lever repeater relay 9 has a stick circuit controlled by a back contact of the associated normal level repeater relay f, and has a pick-up circuit controlled by a reverse contact of a switch lever k of Fig. 2 or 2 or of a switch lever y of Fig. 6.

Each lock relay R is controlled by the associated polarized switch control relay m and by the associated normal and reverse lever repeater relays J and g as Well as by one or more track relays T and by an approach locking relay designated by the reference character P with a distinguishing exponent, shown in Figs. 2 and 2 and also by one or more route locking relays designated by the reference character V with a distinguishing exponent.

The tracks relay T for the first track section in advance of each of the groups of signals S and S controls, in part, a repeater stick relay designated by the reference character U with an exponent corresponding with that of the track relay by which it is controlled.

Each approach locking relay P shown in Figs. 2 and 2 is so controlled that it becomes deenergized when a signal for a route with which it is associated is controlled to indicate proceed. Each route locking relay V is so controlled that it becomes deenergized when an approach locking relay P for a route which it controls is deenergized. Each relay V can then be renergized if the associated relay P is again energized before a train enters its route at the signal. Each relay V, after a train enters its route while its associated signal is indicating proceed, can be reenergized only after the train has left a given portion of its route.

In each of the drawings, the contacts operated by the various relays or by the time release J or by other control devices including the control levers shown in Figs. 2 and 6 are identified by numbers, such numbers having distinguishing exponents when the contacts are shown elsewhere than adjacent the respective relay or release or other control device by which they are operated.

The exponent for each of these contact numbers comprises the reference character and exponent for the respective relay, release or other control device by which the associated contact is operated. For example, the exponent T for contact I09 shown in the circuit for relay V in Fig. 1 comprises the reference character T and its exponent 2 for the track relay T which operates contact I09. Similarly, exponent V for contact 45 shown in the circuit for relay R in Fig. 1 comprises reference character V and its exponent 3 for relay V which operates contact 45 In Figs. 2 and 2*, two groups of contacts are shown for time release J. Different types of contacts operated by release J are distinguished by the exponents a and b, and the contacts which are shown in Fig. 2 separate from release J have the additional exponent character J.

In Figs. 2 and 2 a track diagram or track model is shown together with representations of signals S, the locations of which representations with respect to the track diagram correspond to the locations of the signals with respect to the tracks shown in Figs. 1 and l Indicator lamps e controlled by various track relays T are shown mounted in the track model in locations corresponding to the locations of the associated track circuits.

Adjacent the track model, switch control levers are shown, one for each switch, designated by the reference character It with an exponent corresponding to that of the switch it governs. Each switch lever is has normal and reverse positions n and r for controlling energizationof normal ZZ is controlled by push button circuit controland reverse lever repeater relays f and 9, respectively, shown in Fig. 1

Three indicator lamps are shown adjacent each of these switch levers. Considering the -lamps adjacent lever is, for example, lamp e is lighted when normal lever repeater relay f and normal switch indication relay 2' are ener-' gized, thus indicating that switch H is in its normal position in agreement with the energization of the normal lever repeater relay; lamp c is lighted when reverse lever repeater relay 9 and reverse switch indication relay t are energized,

indicating when switch H is in its reverse position in agreement with the energization of reverse lever repeater relay g and lamp e is lighted when lock relay R is deenergized, indicating that the energization of switch control relay m can not be changed to cause operation 7 the lamps for lever 70*, and hence their circuits are omitted from the drawings.

Signal control levers designated by the reference characters u and u are shown below switch levers In. Each of the signal control levers t has a normal position it, a reverse position to the left 1), and a reverse position to the right 1. Lever w, when moved to its 10 position, controls the clearing of signals S and, when moved to its r position, controls the clearing of signals S and S Lever u when moved to its 1' position, controls the clearing of signals S and, when moved to its 39 position, controls the clearing of signals S and S Lever u when moved to its 1' position, causes the energization of a preliminary signal control relay Z for controlling signals S provided no opposing signal is controlled to display the proceed indication. When lever u is moved to its p position, it causes the energization of a second preliminary signal relay 2 for controlling signal S or 8, provided no opposing signal is controlled to display the proceed indication. A call-on signal relay Z2 is controlled in part by a push button circuit controller contact w for causing signal S to display a call-on indication.

Signal relay Z is controlled in part by lever u in its r position, and a signal relay Z is controlled in part by lever u in its p position similarly to the manner in which relays Z and 2 are controlled by lever u Call-on control relay ler w similarly to the manner in which relay ZZ is controlled by push button circuit controller contact w The circuits for relays 2 Z and Z2 are therefore omitted from the drawmgs.

Four indicator lamps are shown adjacent each signal lever u. Considering the lamps for lever u lamps c and e may be of one color, white for example, while lamps e and e may be of a different color, such, for example, as red, to make the indicators more readily distinguishable. The lighting of lamp 6 indicates that although lever u is in its right-hand position and relay Z is energized for clearing one of the signals S a corresponding signal control relay Y has not become energized. Similarly, the lighting of lamp 6 indicates that although lever 11) is in its left-hand position and relay Z is energized for clearing one of the signals S or S the corresponding signal control relay Y has not become energized. The lighting of lamp e for signals S1 indicates that none of these signals can be cleared because an opposing signal has been'cleared. Similarly, the lighting of lamp e indicates that neither signal S nor S can be cleared because an opposing signal has been cleared.

Approach locking relays are designated by the reference character P with distinguishing exponents corresponding to those of the associated signal relays Z. Each of these approach locking relays is controlled in part by its signal relay Z.

Time releasing of approach locking relays P is controlled by the time releasing device J which may be of the normally unwound clockwork type. Group releasing of approach locking relays P is provided, that is, the one release J controls the 3 locking relays P, time release J must first be wound up to open the six normally closed contacts and to close the normally open contacts 259 and MW and thereby cause the energization of one or the other, or both, of two slow releasing relays N and N respectively. Relay N enters into the control of approach locking relays P and P whereas relay N similarly enters into the control of approach locking relays P and P When time release J is permitted to run down after being fully wound up, contacts 259 and MW will open as release J leaves its fully wound position, and contacts 266 268 253- and 25E": will close upon the lapse of a measured interval of time after the beginning of the unwinding operation. Upon the lapse of a further meas-' For each route with which a relay X is associated, a signal lock relay, designated by the reference character I with an exponent corresponding to that of the relay X for an opposing signal, is controlledin series with the relay X for the route. Energization of any route relay X causes energization of the relay I which is in series with it, and the relay I then prevents energization of the signal relay Z for the opposing signal of the same route.

In Fig. 4, circuits are shown for relays, designated by the reference characters L and L which are termed signal slotting relays. Relay L enters into the control of signal S, and relay L enters into the control of signal S.

Fig. 5 shows circuits which constitute What is known as a signal control relay or route circuit network. A signal control relay for controlling each signal, and designated by the reference character Y with an exponent corresponding tothat of its signal, is controlled by these circuits.

nals which these levers control.

and 2 is here shown. A difierent type of control lever for the switches and signals is, however, provided for mounting in the track model adjacent the diagrams of the switches and sig- Each of these switch and signal levers or keys is designated by the reference character y with a distinguishing exponent similar to that of the switch or signal which it controls. Lever y for controlling signals S and lever 1/ for controlling signals S have normal positions n, reverse positions r, and lower or call-on positions 2. Each of the other signal levers and each of the switch levers has only two positions, a normal and a reverse position, designated by the reference characters n and r, respectively.

Signal relays Z and call-on control relays ZZ are controlled by the signal levers of Fig. 6 similarly, in general, to the relays Z and ZZ of Figs. 2 and 2 Only the circuits for relays Z ZZ and Z are shown, since the circuits for the other relays Z and ZZ, controlled by the signal levers of Fig. 6, are similar to the circuits for relays Z and ZZ Only one indicator lamp is shown for each switch and signal lever of Fig. 6. Each of these lampsis shown enclosed by its lever, and is designated by the reference character c with a distingui'shing exponent corresponding to that of its lever.

A signal indication relay, designated by the reference character D is shown for controlling in part the signal indicator lamp c for signals S This lamp is controlled by a signal lock relay 1 to display a steady light if the signal relay for the associated signal is prevented from being energized because an opposing signal is controlled to display a proceed indication. When lever y is in its normal position, as shown in the drawings, relay I is deenergized, lamp 6 is controlled by a contact 239 of a coding device W to display a flashing light if relays Z2 and Z are both deenergized. When lever y is moved to its reverse position or to its call-on position, lamp 8 will display a flashing light until a signal control relay Y for one of the signals S becomes energized. Circuits for controlling other signal lever lamps e are similar to those just described for lamp c and are therefore omitted from the drawings.

Coding device W may be of a type having a control winding 28%, a control contact 28? which is biased by a spring 288 to the position in which it is shown in the drawings, and a contact 289 0perated in conjunction with contact 281. With contact 231 in the position in which it is shown in the drawings, a circuit is completed for energizing winding 288, passing from terminal a: of a source of current not shown in the drawings, through contact 287, and winding 28$ of coder W to terminal 0. Winding 286, when thus energized, attracts contact 28? until contact 28$ closes and contact 28?? opens. Spring 288 then returns contact 287 as far as the position in which it is shown in the drawings, and momentum may carry contact 28? beyond the position in which it is shown in the drawings. Winding 286 then pulls contact 281 back again, causing the operation to be repeated. Contact 289 becomes closed each time winding 236 attracts contact 281', and opens when spring 288 returns contact 28! to the position in which it is shown in the drawings'. Coding device W may be designed to open and close contact 289 at any suitable rate, for

"example of the'order of 180 times per minute.

Normal and reverse switch lever repeater relays and g are controlled by switch levers y, similarly to the manner in which such relays are shown controlled by lever 70 in Fig. 1 Normal and reverse switch indication relays i and t are controlled similarly to the way in which relays i and t respectively, are shown controlled in Fig. 1 Lock relays R are controlled as shown in Fig. 1 The circuits for relays f, g, i, t and R are therefore omitted from Fig. 6.

Each switch lever lamp 6 is controlled to display a steady light if its lock relay R is deenergized while its normal or its reverse indication relay 2' or t is energized to correspond with its normal or its reverse lever repeater relay or g, respectively. Each switch lever lamp e is controlled to display a flashing light if its indication relays i and t do not correspond in the energized or deenergized condition with its lever repeater relays J and g, respectively. Circuits are shown for lighting lamp e but are omitted for the other switch lever lamps because the circuits for these other lamps are similar to the circuits shown for lamp e Figs. '7 and 7 show communication circuits for reducing the number of line wires between the switch and signal locations and the point of control when the intervening distance is long, or when for some other reason the addition of such communication circuits is desirable. A portion of the apparatus of Fig. 6 is shown modified for use with such communication circuits. The rest of the apparatus of Fig. 6 could be similarly modified for such use, and is therefore omitted from the drawings.

Lever y of Fig. 7*, when moved to its r position, completes an energizing circuit for a signal lever relay Q through a back contact of a signal lever call-on relay K Lever y when moved to its a position, completes an energizing circuit for relay K through a back contact of relay Q Lever relays-Q and K control signal and call-on communication relays Q and K respectively. By using two sources of unidirectional current, such, for example, as batteries yy and 22, and by using two asymmetric units 12 and 12 such, for example, as the well-known copper oxide rectifier valve, relays Q and K are controlled over the same pair of line wires comprising control wire M8 and a common conductor 0. Communication relays Q and 1?, in turn, control signal and call-on relays Z and ZZ respectively.

Normal and reverse switch lever repeater rclays .f and g are controlled by switch levers y, similarly to the manner in which relays f and g are shown controlled by lever 70 in Fig. l Con trol circuits for relays and g are therefore omitted from Figs. '7 and 7 Lever repeater relays f and g are shown controlling normal and reverse switch lever communication relays f and 9 respectively, through valves 0 v 12 and 0 a conductor 365, and the common conductor 0. Each asymmetric unit or valve 2; permits current to flow freely in the direction indicated by the arrowhead portion of its symbol, but prevents the flow of sufficient current in the opposite .direction to operate the associated relay. Relays i and 9 enter into the control of polarized relay m and lock relay R similarly to the manner shown for relays f and g in Fig. 1'.

Normal and reverse indication communication relays i and t are controlled over conductors 3M and c by normal and reverse indication relays i and t respectively; switch lock communicating relay R is controlled over conductors 342 and c by lock relay R signal lock communication relay I and a signal indication communication relay b are controlled over conductors 343 and c by signal lock relay I and signal indication relay b respectively; and track repeater communication relays T and T are controlled over conductors 344 and c by track relays T and T respectively. By the use of a coding device W which is similar to coding device W of Fig. 6, relays 'I and T may be controlled to contemporaneously retain their contacts in the attracted position.

Switch and signal lever indication lamps e are controlled by communication relays, similarly to the manner in which these lamps are controlled by the associated indication or control relays in Fig. 6. The coding device W which is also similar to coding device W of Fig. 6, causes switch and signal indicator lamps e to at times display flashing indications.

Having described, in general, the arrangement and operation of various forms of apparatus embodying our invention, we will now trace in detail the operation of these various forms of apparatus.

As shown in the drawings, all parts are in the normal condition, that is, each track relay T is energized; each switch and signal lever R: and u, respectively, of Figs. 2 and 2 and each switch and signal lever y of Figs. 6 and '7 is normal; each switch If is in its normal position in which it is shown; each signal S is in its stop position;

and relays g, t, Z, ZZ, N, X, I, Y, I), K, Q, tt, II,

bb, TT, gg, QQ and KK are deenergized.

We will first trace the operation of the form of apparatus shown in Figs. 1 to 5, inclusive.

With relay T energized, a pick-up circuit for relay P of Fig. 2 is closed, passing from terminal :1), through contacts I3 I4 |5 contact l6 of relay Z contacts and l8' and the winding of relay P to terminal 0. A stick circuit is also closed for relay P and follows the path just traced for the pick-up circuit as far as contact l'l and then passes through the front point of contact IQ of relay P to the winding of relay P With relays T T and '1 energized, pickup and stick circuits are closed for relays P P and P respectively. These pickup and stick circuits are similar to those just traced for relay P and may therefore be readily traced on the drawings without further explanation.

With switch H in its normal position, switch indication relay h is energized, in the normal direction, by a circuit which includes pole-changer 5 of switch H in its normal position. With switches H and I-I in their normal positions, relay h is energized, in the normal direction, by a circuit of a well-known type and which includes pole-changers 6 and I of switches H and H respectively, in their normal positions. Circuits for energizing switch indication relays h and h are similar to the circuits just described for relays h and 7%, respectively, and are therefore omitted from the drawings.

With lever k in its normal position, normal lever repeater relay f? is energized by a pickup circuit passing from terminal at, through contact 39 closed in the 12 position, and the winding of relay f to terminal 0. A stick circuit for relay f is also closed, passing from terminal :12, through contact 40 of relay g contact 4| of relay f and the winding of relay f to terminal 0. Pickup and stick circuits are also closed for energizing relays i f and f ljhe pickup circuits for controlled by relays 9 g and g similarly to the manner in which the stick circuit for relay f is controlled by relay g*- The pickup and stick circuits for relays I I and f are therefore omitted from the drawings.

A route locking relay, designated by the referi ence character V is energized by circuits which will presently be described. With this relay ener- I gized, and with relays T P and f energized, a pickup circuit is closed for relay R passing from terminal :r, through contact 44 of relay T contacts 45 and 46 winding of relay R contact 62 of relay f and contact 63 of relay m in its normal position to terminal 0. A stick circuit for relay R is also closed, following the path just traced for the pickup circuit as far as the winding of relay R and thence through contact 66 of relay R to terminal 0. A stick circuit is closed for relay R passing from terminal x, through contacts 48 49 50, 5| and 52', winding of relay R and contact 66 of relay R to terminal 0. A stick circuit is closed for relay R passing from terminal :0, through contacts 53 54 55 56 51', and 58 winding of relay R and contact 66 of relay R to terminal 0. A stick circuit is closed for relay R passing from terminal :0, through contacts SQ Sli and GI, winding of relay R and contact 66 of relay R to terminal 0. A pickup circuit is also closed for each of the relays R R and R following the stick circuit as far as the Winding of each of these relays, and thence passing through a contact of an associated normal lever relay 1 and a normal polar contact of an association polarized switch control relay m, similarly to the pickup circuit traced for tact 64 of an associated reverse lever relay g and a reverse polar contact 65 of an associated polarized switch control relay m.

With relays f and R energized, a normal pickup circuit is closed for relay m passing from terminal :12, through the back point of contact 61 of relay g front point of contact 68 of relay f front point of contact ll of relay R winding of relay m front point of contact l2 of relay R front point of contact 13 of relay f and the back point of contact 14 of relay 9 to terminal 0. Circuits for energiz ng re ays m m and m are similar to the circuits for relay m and are therefore omitted from the drawings.

With relay m energized by current of normal polarity, normal control magnet nn for motor M I is energized by its circuit passing from terminal :1:, through contact ll of relay m contact l2 of relay m in its left-hand position, and the winding of magnet 1m to terminal 0. The circuitfor lock magnet q of motor M is, however, open at U ergizing normal indication relay 2' passing from terminal at, through a resistor 3%, contact 65 of relay m in its left-hand position, contact 69 of relay m contact 18 of relay 2%, winding of relay 2', contact 18 of relay h in its left-hand position, and contact 79 of relay h to terminal 0. The circuits for energizing relays i i and i are similar to the circuit just traced for relay i and are therefore omitted from the drawings.

Circuits for energizing relays 75 t and t are similar to the circuit shown, and which will be traced hereinafter, for relay t and are therefore also omitted from the drawings.

With lever 70 in its 12 position, and with relays f and i energized, indicator lamp e shown in Fig. is energized by a circuit pass ng from terminal ac, through contacts 238 and 239, contact 240 of lever 10*, and lamp 6 to terminal 0.

With the various relays P, T, U, 72 and i energized, one or more pickup and stick circuits are closed for each of the route locking relays V. For example, a pickup circuit for relay V is closed, passing from terminal :13, through contacts SW M 83 84', and the winding of relay V to terminal 0. A second pickup circuit is also closed for relay V which is the same as the pickup circuit just traced except that it includes contact 82 instead of contact 8l A third pickup circuit for relay V is also closed, and is the same as the first pickup circuit except that it includes contact 86 instead of contact 85 A stick circuit for relay W is closed, passing from terminal at, through contacts Mi and 8I contact 8'! of relay V and the winding of relay V to terminal 0. A second stick circuit for relay Vziie is also closed, and is the same as the first stick circuit except that it includes contact 82 instead of contact M With relays T and P energized, a pickup circuit is closed for track repeater stick relay U passing from term nal as, through contact N5 of relay T contact I "S and the winding of relay U to terminal 0. A stick circuit for relay U is also closed, passing from terminal a:, through contact N5 of relay T contact I20 of relay U and the winding of relay U to terminal 0. Relay U is also energized by similar pickup and stick circuits which, on account of the circuits for relay U having been traced, may be readily followed on the drawings.

On account of the various relays T and U being energized, each of the signal slotting relays L is energized. The circuit for relay L passes from terminal as, through contacts I26 I21, 128 I29, H0, and I3l' and the winding of relay L to terminal 0. Relay L is energized by a similar circuit which may be readily followed on the drawings.

We will assume that the operator in charge desires to arrange for a traffic movement from A to E. Since each of the switches H H and H is in its normal position in which it is required for this route, it will not be necessary for the operator to change the position of any of the switch levers Ic. He will therefore need to operate only signal lever u which he will move to its 7' position, thereby completing a circuit for energizing relay Z passing from terminal :1:, through contact I38 of lever u contact l39 and the winding of relay Z to terminal o Relay Z upon becoming energized, causes lamp 6 to become energized by its circuit passing from terminal at, through contacts l3 M and 15 front point of contact H30 of relay Z and lamp e to terminal. 0. Relay Z upon becoming energized, opens its back contact I6, thereby causing relay P to become deenergized.

Relay P upon becoming deenergized, opens, atits contact 56 the pickup and stick circuits for relay R causing this relay to also become deenergized. Relay P upon becoming deenergized, also opens its contact 88, causing relay V to become deenergized.

Relay V upon becoming deenergized, opens its contacts and 45 in the pickup and stick circuits for relays R and R respectively, causing both these relays to become deenergized.

Relay R upon becoming deenergized, opens, at the front points of its contacts H and 12, the normal energizing circuit for relay m and then closes, at the back points of these contacts, a normal stick circuit for relay m passing from terminal as, through resistor 346, contact 65 of relay m in its left-hand position, contact 69 of relay 11 back point of contact H of relay R winding of relay m back point of contact 12 of relay R contact ill of relay m and contact 63 of relay m in its left-hand position to terminal 0. Relays R and R upon becoming deenergized, similarly open normal energizing circuits for relays m and m and close normal stick circuits for these relays. Therefore, as long as relays R R and R remain deenergized, the direction of energization of relays m m and m can not be changed, but these relays will be retained energized in the normal direction by their normal stick circuits.

Relay R upon becoming deenergized, completes a circuit for lamp e passing from ter-- minal :12, through contact 24I and lamp e to terminal 0, causing this lamp to be lighted. Lamps 6 and e are similarly lighted when relays R and R become deenergized.

Relay P upon becoming deenergized, opens its contact 8I in various circuits for relay V but this relay will be retained in its energized condition by circuits through contact 82 Relay P upon becoming deenergized, also opens its contact 6 in the pickup circuit for relay U which, however, remains energized by its stick circuit previously traced.

With relays E, R R R and V deenergized, and with relay Z energized, a circuit is completed for energizing route relay X and signal lock relay 1 passing from terminal as, through contacts I4I and M2 winding of relay 1 back point of contact 143 contacts I44, 946 Ml M8 M9 l50 front point of contact IBI contact I52, and the winding of relay X to terminal 0. Energization of relay I causes lamp c to become energized .by a circuit passing from terminal at, through contacts 2ll and 2!, back point of contact I13 of relay 2 contact I 'M and lamp e to terminal 0. Energization of relay X while relays R R R and V are deenergized, causes signal control relay Y to become energized by a circuit passing from terminal 1:, through contacts H5 and i'l6 back point of contact l'll contacts H8, H9, l8l I82 183, M front point of contact I85 contacts I86, 18?, M8, "39 contact I of relay Y and the winding of relay Y to terminal 0.

Relay Y upon becoming energized, opens, at its back contact l3 the circuit previously traced for lamp e causing this lamp to become extinguished. Relay Y upon becoming energized, causes the arm of signal S to be operated to the proceed position by its circuit passing from terminal a, through contact 231", and the mechanism of signal S to terminal 0.

If, while the arm of signal S is in its proceed position, the operator should forget, and should attempt to arrange a different route by reversing one of the switch levers W, k or 70 before a train passes signal S, the route already arranged will not be affected, and the arm of signal S will remain in its proceed position until the operator moves signal lever u away from its T position, or until a train passes signal S If, for example, the operator reverses lever k while lever u is in its 1' position and signal S is displaying the proceed indication, relay 9 will become energized by is pickup circuit passing from terminal at, through contact 39 in its 1 position, and the winding of relay g to terminal 0. Relay 9*, upon becoming energized, opens its contact Ml in the stick circuit for relay j which thereupon becomes deenergized since its pickup circuit is also open at contact 39. A stick circuit is then completed for relay g passing from terminal :17, through contact 32 of relay I, contact 43 of relay g and the winding of relay g to terminal 0. With relay R deenergized, this change in condition of relay f and relay 9 can not affect the energization of relay m Similarly, a change in the energized condition of relays f and g or f and Q can not afiect the energization of relays m and m respectively, on account of relays R and R being deenergized.

We will now assume that, with signal S displaying the proceed indication for a trafiic movement over the route from A to E, and with each of the levers k in its normal position, an eastbound train arrives on the approach section a-A, and that the operator then desires to stop the train at signal S and send it over some other route than that from A to E. If, for example, he should desire to send the train over the route from A to F, he will return lever u to its 71. position, thus deenergizing relay Z by opening contact I38 of lever c in the circuit previously traced for relay Z Relay Z upon becoming deenergized, will open, at the front point of its contact E51 the circuit previously traced for relays I and X causing these relays to become deenergized.

Relay 1 upon becoming deenergized, will extinguish lamp e on account of the opening of contact 174 Relay X upon becoming deenergized, will open, at the front point of its contact l the circuit previously traced for relay Y causing relay Y to become deenergized. Relay Y upon becoming deenergized, will open its contact 23! in the operating circuit for signal S causing the arm of this signal to return to the stop position.

Relay P will still not become energized, even though signal S has been returnedjto the stop condition, because the pickup circuit for relay P previously traced is now open at contact l8 In order to energize relay P, the operator will wind release J up, causing its normally closed contacts 248, 253 255 26%, 2% and 263 to open, and causing its normally open contacts 245 and 259 to become closed.

Contact 246 now completes a pickup circuit for energizing relay N this circuit passing from terminal :12, through contacts I3 ld l5 contact it of relay Z contact ll back point of contact 19 of relay P front point of contact 245 of relay P contact 246 and the winding of relay N to terminal 0. Relay N upon becoming energized, will complete its stick circuit, which is the same as the pickup circuit just traced except that it includes contact 241 of relay N instead of contact 246-.

After having wound release J to close contact 246% the operator will permit release J to start its unwinding operation. Contacts 245W and 259 will open as soon as the unwinding operation starts. Upon the lapse of a measured period of time after the beginning of the unwinding operation, contacts 253*" 255, 266 and 2G8 will close, but the closing of these contacts will not complete a pickup circuit for relay P the lapse of a further measured period of time, contacts 248 and 2'5! will close,

Contact 248 thereby completes a pickup circuit for relay P following the path of the pickup circuit previously traced for relay P as far as contact VP, and thence passing through contact 248 contact 254 of relay N and the winding of relay P to terminal 0. Relay P upon becoming energized, will complete its stick circuit previously traced. Relay P upon becoming energized, opens at the back point of its contact IS, the stick circuit for relay N which is thereby deenergized. Relay P upon becoming energized, completes, through its contact 59 the pickup circuit for relay R which becomes thereby energized. Relay P closes its contact 88 in the pickup circuit for relay V causing relay V to also become energized. Relay V upon becoming energized, completes, at its contacts and 55 the pickup circuits for relays R and R causing these relays to again become energized. Relay R upon becoming energized, opens, at its contact Hi the circuit previously traced for lamp 6, causing this lamp to be extinguished. Relays R and R upon becoming energized, similarly cause lamps e and e to become extinguished.

The operator will now move lever k to its 1" position, thereby opening contact 240 in the circuit for lamp e and so causing this lamp to become extinguished. With lever 12* in its 1 position, relay 9 will become energized by the pickup circuit previously traced, causing relay 1 to become deenergized, whereupon the stick circuit previously traced for relay 9 Will be completed. With relay f deenergized, the pickup circuit previously traced for relay R is open at contact 62 of relay f but relay R continues energized by its stick circuit previously traced. With relay g and relay R now energized, and with relay f deenergized, the reverse energizing circuit for relay m will be completed, passing from terminal x, through the front point of contact 61 of relay 9', back point of contact E3 of relay f front point of contact 12 of relay R winding of relay m in multiple with resistor 15, front point of contact H of relay R back point of contact 68 of relay f and the front point of contact 74 of relay 9 to terminal 0.

As soon as relay m reverses its contact 65, a second pickup circuit will be completed for relay R which is the same as the pickup circuit previously traced for this relay as far as its winding, and which thence passes through contact 64 of relay g and contact 65 of relay m in its right-hand position, to terminal 0. With relay m energized in the reverse direction, the circuit previously traced for relay i is open at the lefthand position of contact 65, and hence relay 1' becomes deenergized. I

With relay 2' deenergized, a circuit is now completed for the lock magnet q of switch motor M passing .from terminal .r, through contact Upon except including contact 211 of relay 2', contact 218 of relay t and magnet q to terminal 0. With relay m energized in the reverse direction, a circuit is completed for energizing magnet T7 of switch motor M passing from terminal :5, through contact ll of relay 1921*, contact l2 of relay m in its right-hand position, and the winding of reverse magnet T1 to terminal 0. With lock magnet q and reverse magnet r1- energized, motor M will move switch H to its reverse position causing pole-changer 5 to be reversed.

Pole-changer 5, upon becoming reversed, causes relay k to be energized in the reverse direction, thereby completing a circuit for reverse indication relay t passing from terminal at, through resistor 346, contact 63 of relay m in its right-hand position, contact ill of relay m contact ll of relay i winding of relay i contact 18 of relay h in its right-hand position, and contact 79 of relay h to terminal 0. Relay t upon becoming energized, opens, at its contact 218, the circuit traced for lock magnet q. With lever 70* in its 1" position, and with relays g and energized, indicator lamp c will become lighted by a circuit passing from terminal x, through contacts 262 and 243 contact 244 of lever M, and lamp c to terminal 0.

The operator Wfll now again move lever u to its r position, causing relay Z to again become energized by its circuit previously traced. Lamp e will be thereupon lighted as previously described. Energization of relay Z opens the circuit for relay P as before. Relay P upon becoming deenergized, opens the circuits for relays R and W as previously described. Relays R R and R are therefore again deenergized, and hence the normal energizing circuits for relays m and m are open and the normal stick circuits for these relays are closed. With relay R deenergized, the reverse energizing circuit for relay m is open and a reverse stick circuit is now closed for relay m*, which is similar to the normal stick circuit previously traced except that it includes contacts 63 and 65 in the right-hand position instead of in the left-hand position.

Relay X Will now be energized by a circuit which is the same as its circuit previously traced I45": instead of contact l M. Relay X upon becoming energized, completes a circuit for energizing relay Y which, except including contact I80 instead of contact I19, is the same as the circuit previously traced for relay Y as far as contact llll thence passing through contact I94, contact E9! of relay Y contact I98 of relay Y, and the winding of relay Y to terminal 0. With relay Y energized, the arm of signal S will be operated to its proceed position by a circuit passing from terminal :13, through contact NW, and the mechanism of signal S to terminal 0.

We will now assume that all parts of the apparatus have again been returned to the normal condition and that the operator then clears signal S for a trafiic movement from A to E. We will also assume that the operator clears signal S for a trafiic movement from D to B. The operation of the apparatus for clearing signal S is similar to that previously described for signal S and may therefore be readily followed from the drawings.

We will assume that a train now enters approach section a-A, and that the dispatcher then decides to send the train over the route from A to F. He will, therefore, return the arm of signal S to its stop position, and will then wind up release J and start its unwinding operation as previously described.

We will further assume that after relay N becomes energized, but before relay P becomes energized. a west-bound train enters section dD, and that the operator then decides to send the westbound train over the route from D to C. He will, therefore, return the arm of signal S to its stop position, and will then either Wait for release J to close its contact N8 for energizing relay P before he again winds up the release, or he will at once wind up the release, causing relay N to become energized by a circuit passing from terminal 3:, through contacts 32 33 3 5 contact 35 of relay Z contact 36 back point of contact 33 of relay P front point of contact 258 of relay P contact 259 of release J, and winding of relay N to terminal 0.

Relay N upon becoming energized, completes its stick circuit which is the same as the pickup circuit just traced except including its contact 26% instead of contact 259 of release J. The operator will then permit release J to again unwind. Upon the lapse of a sufiicient period of time, both contacts Mil and 28W of release J will close, causing relays P and P respectively, to become energized. The operator can then cause switches H and H to be reversed as previously described for switch H We will next assume that the operator again clears signal S for a trafiic movement from A to E. We will also assume that an eastbound train passes through approach section a-A into section A-iz'. The train, upon entering Aii, deenergizes relay T which, in turn, by opening its contact H5, deenergizes relay U Relay T upon becoming deenergized, opens its contact 92, thereby preventing energization of relay V as long as the train occupies section Relay U upon becoming deenergized, opens, at its contact I28 the circuit traced for relay L causing relay L to become deenergized. Relay L in turn, opens its contact l89 causing relay Y to become deenergized. The arm of signal S thereupon returns to its stop position because of the opening of contact 237 Relay Y upon becoming deenergized, again completes the circuit for lamp e which is thereby lighted.

As soon as the operator now returns lever to its n position, causing relay Z to become deenergized and thereby extinguish lamp 6 a circuit will be completed for energizing relay P passing from terminal :r, through contacts 13 ld lt contact N5 of relay Z contact ll back point of contact 249 of relay ZZ contact 258 and the winding of relay P to terminal 0.

The train, upon entering track section z'i-y'y', causes relay T to become deenergized. Relay T upon becoming deenergized, opens its contact 94 in the pickup circuits for relay V thus preventing this relay from becoming energized when the train leaves section A2'i and permits relay T to close its contact ca When the train leaves section A-ii, relay U will become energized by its pickup circuit previously traced, permitting relay R to again become energized by its pickup circuit. Relays R and R however, continue deenergized while relay V is deenergized. Relay V will remain deenergized until the train leaves section ii7'7', whereupon relay V will become energized by its pickup circuit passing from terminal at, through contact 88 contact S13 in multiple with contact 9P contacts 92 and 94', and the winding of relay V to terminal 0. Upon the energization of relay V relay R will become energized by its pickup circuit. Relay R will,,however, continue deenergized until the train has passed outof section 7'?'E and has permitted relay T to complete the pick up circuit for relay R We will assume that all parts of the apparatus are again in their normal condition, and that the operator clears signals S for a train to move over the route from A to E. We will further assume that after the train has passed signal S, but before it has passed point E, the oper- 31301 desires o perm t a second train to pass point A. He will, therefore, depress push button contact w shown adjacent lever ta in Fig. 2, thereby completing a pickup circuit for energizing call-on relay 2Z this circuit passing from terminal as, through contact I38 of lever u contact |39 push button contact w contact 214 and the winding of relay ZZ to terminal 0. Relay P is deenergized on account of relay Z being energized, and hence a stick circuit for relay ZZ will be completed, passing from terminal at, through contact 21%, contact 213 of relay ZZ contact 2m and the winding of relay ZZ to terminal 0.

With relay ZZ energized, a circuit will now be completed for energizing relay Y which is the i same as the circuit previously traced for this relay as far as contact ,l86N thence passing through contact l96 contact l9! of relay Y i contact E8 of relay Y, and the winding of relay Y to terminal 0. With relay Y energized, the arm of signal S will be caused to display a call-on indication by its circuit previously traced through contact 23W.

We will next assume that all parts of the apparatus are again in their normal condition, and that the operator desires to arranged for a westbound trafi'lc movement from E to A. He will therefore move lever u to its left reverse position p, thus causing relay 2 to become energized by a circuit passing from terminal :12, through contact 215 of lever u contact HG and the winding of relay Z to terminal 0. Re-

lay 2 upon becoming energized, opens, at its back contact 22, the pickup and stick circuits for relay P which is thereby deenergized. Relay 2 upon closing its contact I13 at the front point, completes a circuit for lighting lamp a, passing from terminal 0:, through contacts 20 and 2t, front point of contact H3, and lamp e to terminal 0.

Relay 1 upon becoming deenergized, opens, at its contact 46 the pickup and stick circuits for relay R causing relay-R to become deenergized. Relay 1 upon becoming deenergized, also opens its contact l85 causing relay V to become deenergized. Relay PH, by opening its contact H! also causesrelay V to become energized. Relay W upon becoming deenergized, opens its contact 49 causing relay R to become deenergized. Relay V upon becoming deenergized, opens its contact 53 causing relay R to become deenergized. Relays R R and R upon becoming deenergized, open the pickup circuits and close the stick circuits for relays m m and m'*, respectively, as

ing from terminal 3:, through contacts I53 and [M winding of relay I back point of contact ISI contacts l50 MW, M8 M7 N and M4 front point of contact M3 contact l and the winding of relay X to i contact H'l contacts ZIH and 202 contact 2&3 of relay Y and the winding of relay Y to terminal 0.

Relay Y upon becoming energized, opens, at its back contact 20*, the circuit previously traced for lamp 6 causing this lamp to become extinguished. Relay Y upon becoming energized, also causes signal S to be operated to the proceed position by a circuit passing from terminal as, through contact 231, and the mechanism of signal S to terminal 0. 1

If, after a westbound train enters section EE and before it has passed signal S the operator decides to send the train over some other route other than the route from E to' A, he will return signal lever u to its n position, causing relay Z to become deenergized. Relay Z upon becoming deenergized, opens, at the front point of its contact l43 the circuit previously traced for relays I and X- which are thereby deenergized. Relay I upon becoming deenergized, opens its contact H4 causing lamp 6" to be extinguished. Relay X upon becoming deenergized, opens, at the front point of its contact |H the circuit previously traced for relay Y which is thus deenergized. Relay Y upon becoming deenergized, opens its contact 23'! in the circuit for signal S thereby causing this signal to be returned to its stop position. With the westbound train occupying section EE relay T will be deenergized, and hence its contact 24' will be open in a normally closed pickup circuit for relay P In order to cause the energization of relay P the operator will new again wind up release J. When release J is fully Wound up, relay N Relay N upon becoming energized, completes'a stick circuit which is the same as the pickup circuit just traced except that it includes contact 247 of relay N instead of contact 2461 As soon as release J is completely wound up, the operator will permit the unwinding operation of this release to begin. Contacts MW and 259 willthen open, and, upon a lapse of a measured interval of time, contacts 286 268 253 and 255 will close. Contact 255, upon becoming closed, completes a pickup circuit for relay P pass-v ing from terminal it, through contacts 26 and 2!, contact 22 of relay Z contacts 23 and 255 contact 255 of relay N and the winding of relay l? to terminal 0.

Relay P upon becoming energized, opens,

at the back point of its contact 245, the stick cir-,

cuit previously traced for relay N Relay N being slow releasing, retains its front contacts closed long enough for relay P to complete its stick circuit which is the same as the pickup circuit traced for relay P as far as contact 23 thence passing through contact 25 of relay P and the winding of relay P to terminal 0. Relay P upon becoming energized, completes, at its front contact 46 the pickup circuit previously traced for relay R Relay 1 upon becoming energized, also completes a pickup circuit for relay W passing from terminal as, through contacts lH 2 and H3, and the winding of relay V to terminal 0. Relay V upon becoming energized, completes its stick circuit passing from terminal at, through contact Hi contact H t of relay V and the winding of relay V to terminal 0. Relay P upon becoming energized, also completes a pickup circuit for relay V passing from terminal at, through contact H35 contact WW in multiple with contact i63 contact W9, and the winding of relay V to terminal 0. Relay V upon becoming energized, completes a stick circuit which is the same as the pickup circuit just traced except that it includes contact MB of relay V instead of contact 09 Upon the energization of relays V and W relays R and R respectively, become energized by their pickup circuits. With relays R R and R again energized, the operator can now arrange some other route for the westbound train.

We will now describe the operation of the second form of apparatus embodying our invention, which comprises the parts shown in Figs. 1 1 a portion of Figs. 2 and 2 and Figs. 3 to 6, inclusive. With the apparatus of Fig. 6 in the condition shown in the drawing, lamp c for lever y which controls signals S is displaying a flashing light controlled by a circuit passing from terminal at, through contact 289 of coding device W, back point of contact 299 of relay b back point of contact 29! of relay Z and lamp c to terminal 0.

We will assume that the operator moves lever g to its 7' position for causing switch H to be operated to its reverse position. Assuming that contact w of Fig. 1 is now operated by lever 1/ of Fig. 6 instead of by lever k of Fig. 2 relay 9 will become energized by its circuit previously traced, and relay f will become deenergized upon the energization of relay Q.

A circuit for causing lamp c of Fig. 6 to display a flashing light will be completed when relay 9/ becomes energized, this circuit passing from terminal :0, through contact 2239 of coding device W, front point of contact 29W, back point of contact 299, and lamp e to terminal 0. As soon as relay f becomes deenergized, a second circuit will be completed for causing lamp e to display the flashing indication, this second circuit passing from terminal a, through contact 289 of coding device W, back point of contact 293, front point of contact 29?, and lamp c to terminal 0.

As soon as relay m has responded to the enerization of relay 9 and has caused normal indication relay 2' to become dcenergized, the second circuit for lamp e will be opened at the front point of contact 291 Lamp e however, will continue to display the flashing light until reverse indication relay t has become energized upon the completion of the operation of switch H to its reverse position.

When the operator returns switch H to its normal position by again energizing relay f lamp e will be caused to display a flashing light from the time relay f becomes energized until relay 2' becomes energized, the circuit for lamp 6 under this condition, passing from terminal :12, through contact 289 of coding device W, front point of contact 293, back point of contact 291 and lamp c to terminal 0. A fourth circuit will also be completed for lamp e for a brief period, this circuit passing from terminal :c, through contact 289 of coding device W, back point of contact 29 i front point of contact 2235), and lamp c to terminal 0.

If, While switch H is in its normal position, relay R should, for any reason, become deenergized, lamp 6 will be energized, to display a steady light, by a circuit passing from terminal as, through contact 295, contact 296 front point of contact 29?, and lamp e to terminal 0. If, when switch H is in its reverse position, relay R should, for some reason, become deenergized, a second circuit will be completed for causing lamp e to display a steady light, this circuit passing from terminal 3, through contact 295 contact 29%, front point of contact 2.98, and lamp 6 to terminal 0.

We will now assume that all parts of the apparatus are returned to the normal condition and that the operator moves lever y to its 1" position for clearing signal S for a traffic movement over the route from A to E. A circuit will be completed for relay Z passing from terminal 1c, through contact 279 contact 280 of lever y closed in its 7* position, and the winding of relay Z to terminal 0. Relay Z upon becoming energized, opens, at the back point of its contact 295, the flashing light circuit previously traced for lamp e Relay Z upon becoming energized, causes relay 21 to be energized by a circuit passing from terminal :B, through contacts ld M and 45 front point of contact of relay Z and the winding of relay 5 to terminal 0. As soon as relay b responds to energization by this circuit, the flashing indication control of lamp 6 will be resumed by a second circuit which is the same as the circuit previously traced except including front points of contacts 290 of relays b and 29! of relay Z instead of the back points of these contacts. As soon as relay Y becomes energized for causing signal S to display the proceed indication, the circuit for relay b will be opened at contact IS and hence the circuit for lamp e will be broken at the front point of contact 29!) of relay b causing lamp e to be extinguished.

If, after the train has passed signal S and before it has passed the point E, the operator decides to send a second train past point A, he will move lever y to its a position, thereby completing a second circuit for relay Z which includes contact 289 closed in the 2 position of lever 31 Upon the energization of relay X1 as previously described, a pickup circuit will be completed for call-on signal relay ZZ passing from terminal r, through contact 279 contact 23! of lever 11 contact 28?, contact 235 and winding of relay ZZ to terminal 0. A stick circuit will then be completed for relay ZZ passing from terminal 3:, through contact 283 contact 284 of relay ZZ contact 285 and the winding of relay ZZ to terminal 0.

If, while lever y is in either its 1' or its a position, the operator should by mistake attempt to clear an opposing signal, such for example as signal S by moving lever 31 to its r position,

relay 2 2l5 of relay I similarly to the manner in which relay Z is shown controlled by contact i3S could not be energized because contact 216 would then be open. It follows that while a given signal is displaying a proceed indication, a mistake in the operation of the lever for an opposing signal would not cause the first signal to display the stop indication.

We will now describe the third form of apparatus embodying our invention, which comprises the second form of apparatus modified as shown in Figs. 7 and 7 As shown in Figs. 7 and 7', none of the indicator lamps e is lighted. With relay f energized as shown in Fig. 1 communication relay i is energized by a-circuit passing from a battery 11y, through contact 303, valve 11'', conductor 345, valve 11 winding of relay f, and conductor 0 back to battery yy.

In this form of apparatus embodying our invention, relays i, t, R, I, b, and T are located adjacent the switch and signal locations. Communication relays at the point of control are energized by circuits controlled by the relays adjacent the switch and signal locations. Communication relay i is energized by a circuit passing from battery yy through contact 305 conductor 34!, valve '0 winding of relay 1', and conductor 0 back to battery yy Communication relay R is energized by a circuit passing from battery 22 through conductor c,'winding of relay R conductor 3 32, and contact 322 back'to battery 22 Communication relays 15, I and b are similarly controlled. by associated relays t 1 and b adjacent the switch and signal layout.

Communication relay T is energized when relay '1 is energized and relay T is deenergized, the circuit for relay 'I passing from battery 22 through conductor 0, winding of relay T valve 12 conductor 3%, front point of contact 321', and contact 325 back to battery .22 Communication relay T is energized by a circuit which is closed when relay T is deenergized and relay T is energized, this circuit passing from battery 1111 through the front point of contact 326', back point of contact 327', conductor 3M, valve o winding of relay T and conductor 0 back to battery yy When both relays 'I and T are deenergized, both relays T" and T are operated, relay T being periodically energized by a circuit passing from battery 1111 through contact 32| of coding device W in its left-hand position, back point of contact 325, back point of contact 32?, valve 0 winding of relay T and conductor 0 back to battery yy Relay T is periodically energized by a circuit passing from battery .22 through conductor 0, winding of relay T valve 11 conductor 3 2-4, back point of contact 321', back point of contact 326', and contact 32! of coding device W in its right-hand position back to battery 22 If the operator desires to clear signal S for a train movement from A to E, he will move lever y to its 7 position, thereby completing a circuit for energizing relay Q this circuit passing from terminal :c through contact 39'! closed in the 1 position of lever y contact 333 of relay K and the winding of relay Q to terminal 0. Relay Q upon becoming energized. completes a circuit for energizing communication relay Q passing from battery 'yy. through contact 3l0 back point of contact 3l2 conductor 34%), valve o winding'of relay Q and conductor 0 back to battery 1111. Upon the energization of relay Q a circuit is completedfor relay Z passing from being controlled through contact terminal :0, through contacts 3I3 and 3I4 and the winding of relay Z to terminal 0. Energization of relay Z causes operation of apparatus for clearing signal S in the manner already described.

If, after a train has passed signal S and before it has passed point E, the operator should desire to send another train past signal S he will move lever y to its .2 position, thereby completing a circuit for relay K passing from terminal :0, through contact 301i closed in the 2 position of lever y contact 309 of relay Q and the winding of relay K to terminal 0. Energization of relay K causes a circuit to be. completed for energizing relay K this circuit passing from battery as over conductor 0, through the winding of relay K valve v conductor 34!), front point of contact 312 B and contact 3! I back to battery e2. Relay K upon becoming energized, completes a circuit for energizing relay Z passing from terminal at, through contacts 3l3 and SIE and the winding of relay Z to terminal 0. Relay Z upon becoming energized, causes the energization of relay X by the circuit previously traced.

With relays K and X energized asjust described, and with relay L deenergized due to the presence of a train between the location of signal S and the point E, a circuit for energizing callon relay Z2 will be completed, passing from termina: :0, through contacts 313 3l6 SIP, and 320 and the winding of relay ZZ to terminal 0. Relay ZZ upon becoming energized, completes its stick circuit passing from terminal :12, through contact 318 'of relay ZZ contact 3l9 contact 326 and the Winding of relay ZZ to terminal 0. Energization of relay ZZ causes the energization of relay Y and 'the operation of signal S to display the call-on indication as previously described.

A train, upon entering track section Aii, causes the energization of communication relay T, as already traced. Relay T upon becoming energized, causes track indicator lamp e to become energized by a circuit passing fromterminal at, through contact 339 and lamp e to terminal 0.

We have described, for a few typical traffic movements, the operation of three forms of apparatus embodying our invention. From those descriptions of operation and from the preceding general description, operation of each of the three forms of apparatus for every other possible traffic movement will be readily understood by reference to the drawings.

Apparatus of each of three forms embodying our invention is shown for a layout including switches which can be arranged for eleven different routes. Traffic movements can be made in either direction over each of these routes. A separate switch control lever is provided for each single switch and for each pair of crossover switches. In the first form of apparatus, two

signal levers are shown for controlling all the signals for governing trafiic movements in both directions over these eleven routes. Each of these levers has a left reverse position for controlling signals for governing westbound traflic movetrolling signals for governing eastbound traific.

movements. In the modifications shown in Figs.

6, 7 and 7 a signal lever is provided for each signal location. The levers associated with s'ignals which provide a call-on indication have an upper or reverse position for controlling the usual signal indications, and have a lower or call-on position for controlling the call-on indication.

In the forms of apparatus-shown in Figs. 6, 7 and '7', only one indicator lamp is associated with each switch and signal lever. Each of these lamps is enclosed by the associated lever, and is controlled to at times display a steady light and to at other times display a flashing light, in order to differentiate between indications.

The switch control circuits for each of the three forms of apparatus are so arranged as to prevent switch control storage, that is, if a switch lever is moved to a position for causing its switch to be operated while other traffic conditions prevent such an operation of the switch, the switch cannot subsequently be operated without a further movement of the switch lever when such other trafiic conditions permit operation of the switch. During thetime that the various traific conditions prevent operation of the switch, the polarized switch control relay is retained energized in its last previous direction of energization by a polarized stick circuit.

For each of the three forms of apparatus, the c its are so arranged that a mistaken operation of a switch lever for causing an operation of a switch in a route for which a signal is indicating proceed will not cause the signal to be put to the stop condition.

With each of the three forms of apparatus, the energization of a signal lock relay in series with a route relay prevents both the possibility of the indication of a clear signal being changed to a stop indication, and the clearing of an opposing signal, if the control lever for the opposing signal is reversed while the control lever for the first signal is in the position for causing the first signal to display the proceed indication.

In interlocking plants which are equipped with mechanically interlocked levers, electrically opera-ted signals are commonly controlled by a circuit network which is somewhat similar to the circuit network shown in Fig. 5. Interlocking of signal controls is accomplished by-the mechanical interlocking between signal levers in interlocking plants which embody mechanical interlocking, whereas in apparatus embodying our invention, an additional circuit network, shown in F. 3, provides interlocking between signal con- The two circuit networks shown in Figs 3 and. 5 of the accompanying drawings serve as a check upon each other, whereas in interlocking plants which embody mechanical interlocking,

usual signal network circuits and the mechanical interlocking between signal levers serve as a check upon each other.

Group releasing or" the approach locking relays provided by the use of one time release, which may be of the clockwork type, together with two slow releasing relays. The time release is provided with contacts which close after a given interval for controlling the approach locking relays for slow speed signals, and is provided with contacts having a longer period of closing for controlling the approach locking relays associated with high speed signals.

One modification of apparatus embodying our invitlon is shown having communication circuits for reducing the number of control and in- .tion conductors between the point of control the switch and signal locations. Lever repeater relays at the control point are repeated at the switch and signal locations by relays which are controlled by given communication circuits. The indication relays controlled by the apparatus at the switch and signal locations are repeated at the control point by relays which are controlled over other'communication circuits.

Although we have herein shown and described only three forms of interlocking control apparatus embodying our invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of our invention.

Having thus described our'invention, what we claim is:

1. In combination, a railway track switch, a lever having a normal contact closed when said lever is in its normal position and having a reverse contact closed when said lever is in a reverse position, a, normal control stick relay, a reverse control stick relay, a pickup circuit for said normal control stick relay including said normal contact, a stick circuit for said normal control stick relay including a back contact of said reverse control stick relay, a pickup circuit for said reverse control stick relay including said reverse contact, a stick circuit for said reverse control stick relay including a back contact of said normal control stick relay, a locking stick relay, a polarized control relay, a'trafiic contact controlled by traffic conditions adjacent said switch, a pickup circuit for said locking stick relay including said traffic contact in series with a front contact of said. normal control stick relay and a normal polar contact of said polarized relay or in series with a front contact of said reverse control stick relay and a reverse polar contact of said polarized relay, a stick circuit for said locking stick relay including said trafiic contact, normal and reverse operating circuits for said polarized relay controlled by said normal and reverse control stick relays respectively and including a front contact of said locking stick relay, normal and reverse stick circuits for said polarized relay including a back contact of said locking stick relay, and means controlled by normal and reverse polar contacts of said polarized relay for operating said'switch to normal and reverse positions respectively.

2. In combination, a railway track switch, a polarized control relay, manually controllable means for energizing said relay by current of normal or of reverse polarity, a polarized indication relay, means controlled by said switch for energizing said indication relay by current of normal or of reverse polarity according as said switch is in its normal or its reverse position respectively, a normal'indication relay, an energizing circuit for said normal indication relay including a normal polar contact of said polarized indication relay and a front neutral contact as well as a normal polar contact of said polarized control relay, a reverse indication relay, an energizing circuit for said reverse indication relay including a reverse polar contact of said polarized indication relay and a front neutral contact as well as a reverse polar contact of said polarized control relay, indication means controlled by said normal and reverse indication relays, and means controlled by normal and reverse polar contacts of said polarized control relay for operating said switch to its normal and reverse positions respectively.

3. In combination, a railway track switch, a lever having a normal and a reverse position, a locking stick relay, a trafiic contact controlled by 

